SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eff31b79e3101e675f1eb668a64e8bbe2b041d1c7a55f2927bcef69c90b16320' 
  AND token = 'G+vmMwwooM6vEGqj0CJKjZdLxioj+Bnk8YNB9sa2sXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}